The present invention relates to an oral virus vaccine and a method of preparing the same.
Viral infectious diseases refer to diseases occurring in hosts infected with viruses. Viruses cause various symptoms depending upon infected sites and infection types. The most common symptoms caused by enteric infection are diarrhea, peritonitis, etc.
As a representative example, porcine epidemic diarrhea (PED) was first reported in Belgium and Britain in 1978 and, thereafter, occurred in many countries (Asia including Japan, China, and South Korea and throughout Europe) in which pigs are raised. In particular, it causes great economic loss in Europe and Asia. The porcine epidemic diarrhea virus (PEDV) causing porcine epidemic diarrhea mainly proliferates in small intestine villous cells and degenerates or necrotizes villus epithelial cells. Accordingly, shrinkage and detachment of villi occur and malabsorption is caused, whereby continuous watery diarrhea occurs. Porcine enteritis occurs regardless of age, and is accompanied by severe diarrhea and dehydration. Further, the mortality rate among piglets can reach 80 to 90%.
In the Republic of Korea, porcine epidemic diarrhea greatly prevailed for two years after the PED virus was first introduced in 1992. At this moment, the PED virus is not clinically distinguishable from transmissible gastroenteritis virus (TGEV), resulting in significant economic damage. Recently, co-infection with the PED virus along with the TGE virus is increasing relative to infection with the PED virus only. Such infection occurs in all seasons, but most frequently occurs in winter. Prevention of the porcine epidemic diarrhea having a high onset rate and mortality rate is of utmost importance. At present, an oral PEDV vaccine for neutralizing external viruses in the intestine is commercially available.
Oral virus vaccines are advantageous in that pain and stress are not encountered upon administration and, accordingly, easy administration is possible. In addition, oral virus vaccines have advantages such as convenient supply and distribution. Oral virus vaccines need to be stably delivered to the intestines, but become unstable in the gastrointestinal tract having a low pH environment due to gastric acid. Accordingly, the effects of vaccines are reduced.
Therefore, there is a need for technology for delivering effectively oral virus vaccines to the intestines, without destruction of the virus vaccines even in a low pH environment.